#include <stdio.h>
#include <stdlib.h>
int main()
{
    double i;
    printf("求实数的绝对值:");
    double zhuanhuan(double x);
       while(scanf("%lf",&i))
       {
        printf("%lf",zhuanhuan(i));
       }
       return 0;
}



double zhuanhuan(double x)
{
    if(x>0)
    {
     return x;
    }
    else
    {
     return -x;
    }
}